I don't remember who, but in one of those "what is chasing the Vasari?" threads somebody theorized that the corruptive influence within the Unity was fury at the TEC passed down through generations, which colored everything they did from that point on. Since the Unity is a collective consciousness, others could theoretically feel that emotion, even if they didn't completely agree with it, and pass it on to others, and so on and so forth. And so basically the Rebels see this and want to return to seeking enlightenment rather than vengeance.

One thing I would like to point out, is that the Advent Rebels left because of their devotion to the Unity, not because they've fractured away from it....  According to the upgraded players manual, the Rebels feel the Unity has become corrupted, and that this sickness should be purged...  So in many ways they could be looked at not as "rebels", but as much more fanatical members of the unity than the Loyalists....  So this apparently didn't spawn from a desire to seperate the Unity, which a hive mind could prevent... ... it spawned from a fanatical devotion to the Unity, and a willingness to do anything, even purging the loyalists, to preserve it.... which in turn might have been caused by having too many fanatics all hooked up to a hive mind..... 

OK, this is just fiction on my part... but wouldn't it make a cool story about the Advent Rebels if that's what happened?  A portion of the original Advent group mind somehow seperated and morphed or corrupted into a hive mind???   That would make them a little more scary...

I'm factoring in the telepathic part...  this is what scares me.  They might be physically weaker than the collective, but if a hive of telepaths could all be controlled and channeled thru one queen, it makes for some interesting possibilities.  Telepathic borg.... not only able assimilate a body, but now also a mind, perhaps from a distance???   Tap into someone's brain and mentally connect them to the hive against their will, from half a continant, or half a solar system, away?

Oh, I should ad, I mean terrifying as a very high compliment... and I suppose mostly from a TEC soldiers POV.... 

Of the three races, I love the concept of the Advent the most, and I do find them the most terrifying of the three... so to speak.  I've played a lot of games against aliens, but the idea of a seperate human race... well, sort of human at this point... "The Deviants from our past..."  OK, I love this idea, and making them a female dominated society as well as physic... that itself would be a huge psylogical threat to a mostly male dominated TEC military command, which I'm assuming form the movies and such it probably is...  that's a nice touch.

It's the idea that most of their power isn't physical, but mental, that I admire most, and find the most frightning, from an enemies point of view.  It's just good Sci-Fi, written into a very well made game... bwaahahahaha